At the present time, conventional compression tests on reciprocating internal combustion engines require connecting a pressure gauge (with an internal check valve) to each cylinder in succession. The engine is then cranked with the starter motor while inhibiting combustion. This process is repeated for each cylinder, and the peak pressures measured on the guage are compared against test limits by the mechanic. If either an excessive difference in compression exists between any two cylinders, or the average compression is below a specified value, one or more engine faults are indicated. These faults might include such things as worn piston rings or cylinders; cracked pistons or cylinder block; misadjusted, worn, or cracked valves; or a defective cylinder head or cylinder head gasket. The compression test is very useful therefore in detecting this class of basic engine faults. However, the time required and inconvenience of performing the test, combined with the need to remove all of the spark plugs or fuel injectors on most engines, results in the mechanic's reluctance to perform the test routinely unless specific performance complaints or fault symptoms have been indicated. Furthermore, if automatic test equipment is to be used for fault detection and isolation, the additional pressure transducers required for practical implementation would be costly and just as inconvenient as the conventional test, if not more so.